/* SWIM2.0 :: Simple website menu
****************************************************************
* DOM scripting by brothercake -- http://www.brothercake.com/
* Licensed under GPL -- http://www.gnu.org/copyleft/gpl.html
****************************************************************
* For professional menu solutions visit -- http://www.udm4.com/ 
****************************************************************
*/

//initialise the menu(s)
//you can replace this with an encapsulated onload if necessary
//http://www.brothercake.com/site/resources/onload/
//you can also take it out of this script and put it somewhere else
window.onload = function() {
    //create a new menu ('menu-id', 'orientation')
    //var verticals = new simpleMenu('menu-v', 'vertical');
    var horizontals = new simpleMenu('menu-h', 'horizontal');
};

//menu object constructor
function simpleMenu(navid, orient) {
    //if the dom is not supported, or this is opera 5 or 6, don't continue
    if(typeof document.getElementById == 'undefined' || /opera[\/ ][56]/i.test(navigator.userAgent)) { return; }
    
    //identify konqueror
    this.iskde = navigator.vendor == 'KDE';
    
    //identify internet explorer [but both opera and konqueror recognise the .all collection]
    this.isie = typeof document.all != 'undefined' && typeof window.opera == 'undefined' && !this.iskde;
    
    //identify old safari [< 1.2]
    this.isoldsaf = navigator.vendor == 'Apple Computer, Inc.' && typeof XMLHttpRequest == 'undefined';
    
    //ul tree
    this.tree = document.getElementById(navid);
    
    //if it exists
    if(this.tree != null) {
        //get trigger elements
        this.items = this.tree.getElementsByTagName('li');
        this.itemsLen = this.items.length;
        
        //initialise each trigger, using do .. while because it's faster
        var i = 0; 
        do {
            this.init(this.items[i], this.isie, this.isoldsaf, this.iskde, navid, orient);
        } while (++i < this.itemsLen);
    }
}

//trigger initialiser
simpleMenu.prototype.init = function(trigger, isie, isoldsaf, iskde, navid, ishoriz) {
    //store menu object, or null if there isn't one
    //extend it as a property of the trigger argument
    //so it's global within [and unique to] the scope of this instantiation
    //which is the same trick as going "var self = this"
    trigger.menu = trigger.getElementsByTagName('ul').length > 0 ? trigger.getElementsByTagName('ul')[0] : null;
    
    //store link object
    trigger.link = trigger.getElementsByTagName('a')[0];
    
    //store whther this is a submenu or child menu
    //a submenu's parent node will have the navbar id
    trigger.issub = trigger.parentNode.id == navid;
    
    //whether this is a horizontal navbar
    trigger.ishoriz = ishoriz == 'horizontal';
    
    //menu opening events
    //onfocus doesn't bubble in ie, but its proprietary 'onactivate' event does
    //which works in win/ie5.5+
    this.openers = { 'm' : 'onmouseover', 'k' : (isie ? 'onactivate' : 'onfocus') };
    
    //bind menu openers
    for(var i in this.openers) {
        trigger[this.openers[i]] = function(e) {
            //set rollover persistence classname -- we have to check for an existing value first
            //because some opera builds don't allow the class attribute to have a leading space
            //don't do persistent rollovers for konqueror, because they stick in kde <= 3.0.4
            if(!iskde) { trigger.link.className += (trigger.link.className == '' ? '' : ' ') + 'rollover'; }
            
            //if trigger has a menu
            if(trigger.menu != null) {
                //show the menu by positioning it back on the screen
                //we can use the same positions as in pure CSS for most browsers ['css']
                //but we have to compute the positions for ie ['compute'] 
                //because it uses position:relative on <a> 
                //whereas the others have position:relative on <li>
                //we also need to use those values for old safari builds ['compute']
                //because the regular positioning doesn't work 
                
                //if this is a horizontal navbar
                //set the left position to auto [css] or compute a position [compute]
                if(trigger.ishoriz) { trigger.menu.style.left = (isie || isoldsaf) ? trigger.offsetLeft + 'px' : 'auto'; }
                
                //if this is a horizontal navbar and a first-level submenu 
                //set the top position to auto [css] or compute a position [compute]
                //otherwise set it to 0 [css] or compute a position [compute]
                trigger.menu.style.top = (trigger.ishoriz && trigger.issub) ? (isie || (trigger.ishoriz && isoldsaf)) ? trigger.link.offsetHeight + 'px' : 'auto' : (isie || (trigger.ishoriz && isoldsaf)) ? trigger.offsetTop + 'px' : '0';
            }
        };
    }
    
    //menu closing events
    //'ondeactivate' is the equivalent blur handler for 'onactivate'
    this.closers = { 'm' : 'onmouseout', 'k' : (isie ? 'ondeactivate' : 'onblur') };
    
    //bind menu closers
    for(i in this.closers) {
        trigger[this.closers[i]] = function(e) {
            //store event-related-target property
            this.related = (!e) ? window.event.toElement : e.relatedTarget;
            
            //if event came from outside current trigger branch
            if(!this.contains(this.related)) {
                //reset rollover persistence classname; not for konqueror
                if(!iskde) { trigger.link.className = trigger.link.className.replace(/[ ]?rollover/g, ''); }
                
                //if trigger has a menu
                if(trigger.menu != null) {
                    //hide menu using left for a horizontal menu, or top for a vertical
                    trigger.menu.style[(trigger.ishoriz ? 'left' : 'top')] = trigger.ishoriz ? '-10000px' : '-100em';
                }
            }
        };
    }
    
    //contains method by jkd -- http://www.jasonkarldavis.com/
    //not necessary for ie because we're re-creating in ie-proprietary method
    //and it would throw errors in mac/ie5 anyway
    //not actually necessary for opera 7 either, because it's already implemented
    //but it won't do any harm, so spoofing doesn't matter
    if(!isie) {
        trigger.contains = function(node) {
            if (node == null) { return false; }
            if (node == this) { return true; }
            else { return this.contains(node.parentNode); }
        };
    }
}
